A precise description of protein dynamics is fundamental to an understanding of the relationship between structure and function for such diverse problems as: the binding of ligands to transport proteins, the catalytic activity of enzymes and the transport of ions through membranes. This proposal involves theoretical and experimental studies of motions in peptides and proteins. Research will be carried out in the following two areas: (I.) Molecular Dynamics and experimental studies of NMR relaxation in the protein pancreatic trypsin inhibitor (PTI), and (II.) Vibrational normal mode studies of model peptides and proteins. The purpose of the projects that comprise this proposal is to develop a firm foundation for interpreting experimental data on the dynamics of biopolymers in terms of the underlying molecular processes.